Documents disponibles écrits par cet auteur

Mapping of crack tip strains and twinned zone in a hexagonal close packed zirconium alloy / M. Kerr in Acta materialia, Vol. 58 N° 5 (Mars 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 5 (Mars 2010) . - pp. 1578–1588 Titre : Mapping of crack tip strains and twinned zone in a hexagonal close packed zirconium alloy Type de document : texte imprimé Auteurs : M. Kerr, Auteur ; M.R. Daymond, Auteur ; R. A. Holt, Auteur Année de publication : 2011 Article en page(s) : pp. 1578–1588 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Synchrotron  diffraction  Fracture  Twinning  Zirconium  Micro-mechanical  modeling Résumé : This paper describes the use of synchrotron X-ray diffraction to map crack tip strain field evolution and initiation of twinning under applied load in a fatigue pre-cracked zirconium alloy. Compact tension specimens were machined in two orientations from a textured rolled plate and loaded along the normal direction and the transverse direction to rolling. Residual strains due to fatigue and the strains introduced at applied KI of approximately 10 and 30 MPa√m were measured for the two specimen orientations. Maps of the region of twinned material were determined. The experimental data is compared to finite element (FE) calculations for the crack tip strain fields and a prediction of the size of the twinned region using a multiscale model based on combining an FE approach with an elastoplastic self-consistent polycrystalline plasticity model. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S135964540900768X [article] Mapping of crack tip strains and twinned zone in a hexagonal close packed zirconium alloy [texte imprimé] / M. Kerr, Auteur ; M.R. Daymond, Auteur ; R. A. Holt, Auteur . - 2011 . - pp. 1578–1588. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 5 (Mars 2010) . - pp. 1578–1588 Mots-clés : Synchrotron  diffraction  Fracture  Twinning  Zirconium  Micro-mechanical  modeling Résumé : This paper describes the use of synchrotron X-ray diffraction to map crack tip strain field evolution and initiation of twinning under applied load in a fatigue pre-cracked zirconium alloy. Compact tension specimens were machined in two orientations from a textured rolled plate and loaded along the normal direction and the transverse direction to rolling. Residual strains due to fatigue and the strains introduced at applied KI of approximately 10 and 30 MPa√m were measured for the two specimen orientations. Maps of the region of twinned material were determined. The experimental data is compared to finite element (FE) calculations for the crack tip strain fields and a prediction of the size of the twinned region using a multiscale model based on combining an FE approach with an elastoplastic self-consistent polycrystalline plasticity model. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S135964540900768X

Study of internal strain evolution in Zircaloy-2 using polycrystalline models / C. Mareau in Acta materialia, Vol. 58 N° 9 (Mai 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 9 (Mai 2010) . - pp. 3313–3325 Titre : Study of internal strain evolution in Zircaloy-2 using polycrystalline models : Comparison between a rate-dependent and a rate-independent formulation Type de document : texte imprimé Auteurs : C. Mareau, Auteur ; M.R. Daymond, Auteur Année de publication : 2011 Article en page(s) : pp. 3313–3325 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Micromechanics  Twinning  Zirconium  Homogenization  Micromechanical  modeling Résumé : In the present paper, an elasto-viscoplastic model is proposed to describe the behavior of hexagonal close-packed materials where multiple deformation modes, including plastic slip and twinning, coexist. The model assists in interpreting the experimental lattice strains whose evolution is often complex because of the many deformation modes involved. The proposed rate-dependent model is compared with a previously developed rate-independent model by studying the development of internal strains in a moderately textured Zircaloy-2 slab. The comparison shows that most of the inflexions that are experimentally observed are well reproduced by the proposed model and the qualitative and quantitative agreement is generally better with the new rate-dependent formulation. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410000911 [article] Study of internal strain evolution in Zircaloy-2 using polycrystalline models : Comparison between a rate-dependent and a rate-independent formulation [texte imprimé] / C. Mareau, Auteur ; M.R. Daymond, Auteur . - 2011 . - pp. 3313–3325. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 9 (Mai 2010) . - pp. 3313–3325 Mots-clés : Micromechanics  Twinning  Zirconium  Homogenization  Micromechanical  modeling Résumé : In the present paper, an elasto-viscoplastic model is proposed to describe the behavior of hexagonal close-packed materials where multiple deformation modes, including plastic slip and twinning, coexist. The model assists in interpreting the experimental lattice strains whose evolution is often complex because of the many deformation modes involved. The proposed rate-dependent model is compared with a previously developed rate-independent model by studying the development of internal strains in a moderately textured Zircaloy-2 slab. The comparison shows that most of the inflexions that are experimentally observed are well reproduced by the proposed model and the qualitative and quantitative agreement is generally better with the new rate-dependent formulation. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410000911

Texture inheritance and variant selection through an hcp–bcc–hcp phase transformation / M.R. Daymond in Acta materialia, Vol. 58 N° 11 (Juin 2010) 

Public ISBD [article]  in Acta materialia > Vol. 58 N° 11 (Juin 2010) . - pp. 4053–4066 Titre : Texture inheritance and variant selection through an hcp–bcc–hcp phase transformation Type de document : texte imprimé Auteurs : M.R. Daymond, Auteur ; R. A. Holt, Auteur ; S. Cai, Auteur Année de publication : 2011 Article en page(s) : pp. 4053–4066 Note générale : Métallurgie Langues : Anglais (eng) Mots-clés : Zirconium  Phase  transformations  Internal  stresses  Neutron  diffraction  Texture Résumé : In situ phase transformation experiments have been carried out using neutron diffraction to monitor the texture evolution during the α → β → α phase transformation in a common zirconium alloy. In contrast to recently reported results by other authors, there is clear evidence of a strong variant selection occurring during the α → β transformation and a weaker variant selection during the β → α transformation. Modeling of the texture change associated with the phase transformation has been successful in describing the variant selection occurring during the α → β transformation, and gives insights into the selection occurring during the β → α transformation. The results are relevant to processing of both zirconium and titanium. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410001576 [article] Texture inheritance and variant selection through an hcp–bcc–hcp phase transformation [texte imprimé] / M.R. Daymond, Auteur ; R. A. Holt, Auteur ; S. Cai, Auteur . - 2011 . - pp. 4053–4066. Métallurgie Langues : Anglais (eng) in Acta materialia > Vol. 58 N° 11 (Juin 2010) . - pp. 4053–4066 Mots-clés : Zirconium  Phase  transformations  Internal  stresses  Neutron  diffraction  Texture Résumé : In situ phase transformation experiments have been carried out using neutron diffraction to monitor the texture evolution during the α → β → α phase transformation in a common zirconium alloy. In contrast to recently reported results by other authors, there is clear evidence of a strong variant selection occurring during the α → β transformation and a weaker variant selection during the β → α transformation. Modeling of the texture change associated with the phase transformation has been successful in describing the variant selection occurring during the α → β transformation, and gives insights into the selection occurring during the β → α transformation. The results are relevant to processing of both zirconium and titanium. DEWEY : 669 ISSN : 1359-6454 En ligne : http://www.sciencedirect.com/science/article/pii/S1359645410001576